Incandescent lamp



No. 750,720. PATENTBD JAN. 26, 1904. W. A. SP'RINGALL.

INGANDESGENT LAMP.

APPLICATION FILED JUNE 25, 1903.

N0 MODEL.

UNiTED STATES Patented January 26, 1904.

I tries.

PATENT INCANDESCENT LAMP.

SPECiEFICATION forming part of Letters Patent No. 750,720, dated January26, 1904.

Application filed June 25, 1903. Serial No. 163,114, (No model.)

To (all whom, it may concern.-

Be it known that I, WALTER A. SPRINGALL, a citizen of the United States,residing at San Antonio, in the county of Bexar and State of Texas, haveinvented new and useful Improvements in Incandescent Lamps, of which thefollowing is a specification.

This invention relates to incandescent lamps of that kind provided witha plurality of filaments which may be alternately thrown into circuit toproduce lights of different candlepower.

The object of the invention is to provide a simple device of thischaracter with caps, either of which may be connected with the lamp toadapt the same either to the so-called Thomson-Houston socket or to theEdison socket.

1n the adaptation of the lamp hereinafter set forth it includes a bulbor globe, a contact, a plurality of filaments in the globe, one end ofeach filament being connected to said contact, and a series of contactsinsulated from each other and from the first-mentioned contact, to whichthe other ends of said filaments are connected, said series of contactsbeing in a substantially common plane at approximately right angles tothe longitudinal axis of the bulb, by virtue of which when the lamp isturned in its cap or socket any one of the filaments may be put incircuit. In the present instance there are three filaments; but thisnumber of course may be either increased or d ccreased.

ln the drawings accompanying and forming a part of this specification,Figure 1 is a perspective view of a lamp including my invention. Figs. 2and 3 are sectional elevations of the same connected, respectively, withthe two caps. Figs. A and 5 are perspective views of said caps.

Like characters refer to like parts throughout the several figures.

The lamp involves the usual bulb or globe 2, closed at its upper end bya seal 3, which is made of some suitable non-conducting matcrial sayplaster-of-paris and is surrounded by the band or casing 4., usuallymade of metal. The bulb 2 incloses a plurality of filamcnts, eachdenoted by 5, and of different candle-power, and one end of eachfilament is connected electrically with a nut 6, constituting a contactand embedded in the seal 3. The opposite ends of the filaments areconnected with contacts, each denoted by 7, which are set into the seal3. The contact or nut 6 is arranged substantially centrally of the sealand projects above the series of contacts ,7, the latter being arrangedconcentrically of the said nut or contact 6. There are three of thesecontacts '7, corresponding in number, of course, with the filaments andarranged substantially in a common plane and at right angles, orsubstantially so, with the longitudinal axis of the bulb or globe 2.

In Figs. 2 and at 1. have shown a cap adapted especially for insertionin what is familiarly known as a Thomson-Houston socket, said cap beingshown in Fig. 2 as connected with the lamp. This cap is denoted by 8 andis in the nature of a thimble, its top being composed of somenon-conducting material, such as vulcanized rubber, while its body isusually made of metal. In the non-conducting top of the cap or thimble 8is countersunk a ring 9, of some suitable conducting material and whichupon the insertion of the cap in the Thomson-Houston socket is adaptedto fit against a corresponding ring in said. socket, which ring is, asis well-known, connected with one leading-in wire for the lamp. Theother leading-in wire is connected with a screw in said socket. l havenot deemed it necessary to show the socket, as it forms no part of theinvention. A spring-arm 10 is inclosed by the cap or thimble 8, and itsbody is connected by screws or their equivalents with the contact-ring9, the said spring-arm being of course insulated from the body of thecap and being adapted to cooperate with the separated contacts 7,hereinbefore described. he top of the cap is centrally perforated toreceive the usual depending screw in the Thomson Houston socket, whichscrew is adapted to engage the central nut or contact 6 upon the lamp. v

When the cap or thimble 8 is fitted in the Thomson-Houston socket, thecentral screw therein, to which a leading-in wire is connected, willdepend through the said central perforation. In use the cap or thimble 8will be inserted in the Thomson-Houston socket, the screw just mentionedprojecting downward through the central perforation in the top of thethimble. The head or banded end of the lamp will be inserted in thethimble, so that the central nut can receive said depending screw. Uponthe connection of these two parts the spring-arm 10, which it will beunderstood constitutes a contact fixed relatively to the contacts 7,will be contiguous to the upper face of the seal 3 in which saidcontacts 7 are set. Then by turning the lamp any one of the contacts 7can be brought into engagement with the free end of the spring arm orcontact 10. When said relatively fixed contact 10 engages any one of theseries of contacts 7, the current will of course pass through thecentral screw in the socket into the nut or contact 6, into a filament5, from the latter to the appropriate contact 7, then to spring-contact10, to the ring 9 and corresponding ring in the socket which, aspreviously stated, I have not shown.

The filaments are of course of different candle-power, and by turningthe lamp any one of the filaments may be brought into circuit. hen thefree end of the spring-arm 10 is between any two of the contacts 7, thelight will be extinguished, or the same result can be secured from theusual switch in the socket,

In Figs. 3 and 5 I have shown a cap to be used in connection with theEdison socket, the latter being interiorly threaded. The modified formof cap is denoted by 11, and it has a head 12, separated from thesubstantially cylindrical body thereof by some suitable insulatingmaterial. The head 12 of the cap is adapted to be connected with theterminal in the socket to which one leading-in wire is connected, theother leading-in wire being connected directly to the socket. Theterminal in question I have not shown. When, however, the cap 11 isinserted in the Edison socket, the head 12 thereof, which of course isof conducting material, engages said terminal, the exterior surface ofthe body of the cap of course engaging the interior surface of the saidsocket. The lamp is the same in each case, it being evident from thisthat the interior surface of both caps is smooth.

The spring-arm 13 is connected in some suitable way to the body of thecap 11 interiorly thereof. The top or head 12 of said cap hasapproximately centrally thereof the depending screw 14:, the two partsusually being made integral. hen the lamp is introduced into the cap 11,the screw will enter and engage into the central nut or contact 6 of thelamp, while the free end of the spring arm or contact 18 will bearagainst the upper surface of the lamp, (which of course is in the planeof the corresponding portions of the series of contacts 7,) whereby onturning the lamp any one of the contacts 7 will be brought intoengagement with the free end of the spring arm or contact 18 to throwthe corresponding filaments in circuit.

The nut or central contact 6 upon the lamp of course projects above theseries of contacts 7, so that when said nut or contact receives eitherone of the screws hereinbefore mentioned the contacts 7 will be inproper position for engagement by the spring-arm 10 or 13, as the casemay be, and when said nut is engaged by either of the screwshereinbefore mentioned the lamp is held in assembled relation withrespect to the socket.

Having thus described my invention, What I claim as new, and desire tosecure by Letters Patent, is

1. The combination of a lamp and a cap rotatably connected thereto, thelamp having a bulb, a contact, a plurality of filaments in the bulb, oneend of each filament being connected to said contact, the latterconsisting of a nut, a series of contacts insulated from each other andfrom the first-mentioned contact to which the other ends of saidfilaments are connected, said series of contacts being in asubstantially common plane at approximately right angles to thelongitudinal axis of the bulb, and the cap having therein a contact toengage any one of said series of contacts upon the rotation of one ofsaid first-mentioned parts with respect to the other and also having inits top a hole registering with said firstmentioned contact or nut.

2. The combination of a lamp and a cap rotatably connected thereto, thelamp having a bulb, a contact, a plurality of filaments in the bulb, oneend of each filament being connected to said contact, a series ofcontacts insulated from each other and from the first-mentioned contactto which the other ends of said filaments are connected, said series ofcontacts being in a substantially common plane at approximately rightangles to the longitudinal axis of the bulb, said first-mentionedcontact consisting of a nut projecting above the top of the lamp, thecap inclosing the top of the lamp, having a hole registering with saidfirst -mentioned contact, and a single spring-contact electricallyconnected with its top and adapted to engage any one of said series ofcontacts upon the turning of one of said first-mentioned parts withrespect to the other.

In testimony whereof I have hereunto set my hand in presence of twosubscribing witnesses.

WVALTER A. SPRINGALL. l/Vitnesses:

J. R. DAVIS, H. E. AIKEN.

